// type ListNode = {
//   val: number;
//   next: ListNode | null;
// };
function creatListNode(val) {
  this.val = val;
  this.next = null;
}

const node1 = new creatListNode(1);
const node2 = new creatListNode(2);
node1.next = node2;
const node3 = creatListNode(3);
node1.next;

type TreeNode = {
  val: number;
  left: TreeNode | null;
  right: TreeNode | null;
};

const tree: TreeNode = { val: 1, left: null, right: null };
